Axions and the strong CP problem in M theory
Abstract
We examine the possibility that the strong CP problem is solved by string-theoretic axions in the strong-coupling limit of the E8×E'8 heterotic string theory (M theory). We first discuss some generic features of gauge kinetic functions in compactified M theory, and examine in detail the axion potential induced by the explicit breakings other than the QCD anomaly of the nonlinear U(1)PQ symmetries of string-theoretic axions. It is argued based on supersymmetry and discrete gauge symmetries that if the compactification radius is large enough, there can be a U(1)PQ symmetry whose breaking other than the QCD anomaly, whatever its microscopic origin is, is suppressed enough for the axion mechanism to work. Phenomenological viability of such a large radius crucially depends upon the quantized coefficients in gauge kinetic functions. We note that the large radius required for the axion mechanism is viable only in a limited class of models. For instance, for compactifications on a smooth Calabi-Yau manifold with a vanishing E'8 field strength, it is viable only when the quantized flux of the antisymmetric tensor field in M theory has a minimal nonzero value. It is also stressed that this large compactification radius allows the QCD axion in M theory to be cosmologically viable in the presence of a late time entropy production.
- Publication:
-
Physical Review D
- Pub Date:
- November 1997
- DOI:
- 10.1103/PhysRevD.56.6588
- arXiv:
- arXiv:hep-th/9706171
- Bibcode:
- 1997PhRvD..56.6588C
- Keywords:
-
- 11.25.Mj;
- 12.60.Jv;
- 14.80.Mz;
- Compactification and four-dimensional models;
- Supersymmetric models;
- Axions and other Nambu-Goldstone bosons;
- High Energy Physics - Theory;
- High Energy Physics - Phenomenology
- E-Print:
- 36 pages, RevTex, No figures